📦 WP-144 — ci: provenance trailers enforced on contributor commits¶
Engineering log · Phase 13 — Contributor admission, augmentation guard and keypoint parity, v0.6.0
🔗 Depends on WP-141 · Needed by none
WP-144 — the layer that produces an artifact, and the contradiction it exposed¶
A trailers job in lint.yml runs check_commit_trailers.py --range over a pull request's own commits. This is the only admission layer producing something reviewable rather than a promise: a contributor must name what an algorithmic change derives from, so an unnamed derivation on a loss or an assigner is visible at review instead of after release.
ci-tests.yml's exemption was right and too wide. Its comment said the trailer contract is a local pre-commit check "because a squash merge replaces the messages this workflow would have validated", which is true of the merge result and false of the submission. Checking the squashed commit validates a message nobody wrote; checking the contributor's own commits validates the ones review actually reads. The comment now says which half it covers rather than reading as a blanket exemption.
Wiring it up exposed a contradiction between the checker and the guide. WP_RE required WP: <digits>, so every commit needed a roadmap row — while D18, and the guide WP-141 had just written, say a change altering no shipped behaviour, no public symbol, no golden and no documented assumption lands without one. Enforced as written, CI would have demanded a row id from exactly the contributors D18 exempts, and the first person to hit it would have been told to invent a number. WP: now also takes the literal none.
none rather than an omitted trailer, and the distinction is the point: it matches how Assumptions: states its own absence, and it makes the message say no row applies instead of leaving a reader to decide whether one was forgotten. Omission is still refused, and so is free text — a test pins each. The other three trailers stay mandatory, because the derivation question does not go away because the tracking did.
The range path had no test at all before this row, in either checker: validate_message was covered and the git walk under it was not. Both now assert that an empty range is clean — a pull request selecting no commit is not one that failed to cite — and the trailer checker additionally validates this repository's own last ten commits, so a regression that let a real message fail surfaces here rather than on a contributor's first pull request.
With this row Phase 13's four-row tail closes. Every numbered row in the roadmap is now ✅; what is not done is not a row — the repository is still private, and O3 still stands between here and the relaxation these four layers were built for.